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Differences in decompression of a high-pressure unit : A case study from the Cycladic Blueschist Unit on Naxos Island, Greece

Peillod, Alexandre; Majka, Jarosław; Ring, Uwe; Drüppel, Kirsten 1; Patten, Clifford 2; Karlsson, Andreas; Włodek, Adam; Tehler, Elof
1 Fakultät für Bauingenieur-, Geo- und Umweltwissenschaften – Institut für Petrographie und Geochemie (Inst. f. Petrograph. u. Geochem.), Karlsruher Institut für Technologie (KIT)
2 Fakultät für Bauingenieur-, Geo- und Umweltwissenschaften – Geologisches Institut (Geolog. Inst.), Karlsruher Institut für Technologie (KIT)

Abstract:

Determining the tectonic evolution and thermal structure of a tectonic unit that experiences a subduction-related pressure temperature (P-T) loop is challenging. Within a single unit, P-T conditions can vary from top to bottom which can only be revealed by detailed petrological work. We present micropetrological data from the middle section of the Cycladic Blueschist Unit (CBU) in Naxos, Greece, which indicates a different P-T loop than that for the top of the sequence. Using Zr-in-rutile and Ti-in-biotite thermometry coupled with quartz-in-garnet elastic barometry and phase equilibrium thermodynamic modeling, we identify a prograde path from 15.4 ± 0.8 kbar to 19.9 ± 0.6 kbar and from 496 ± 16 °C to 572 ± 7 °C (2σ uncertainty), equilibration during decompression at 8.3 ± 1.5 kbar and 519 ± 12 °C followed by near-isobaric heating to 9.2 ± 0.8 kbar and 550 ± 10 °C (or even 584 ± 19 °C), and a final greenschist-facies equilibration stage at 3.8 ± 0.3 kbar and 520 ± 4 °C. We compare these P-T estimates with published data from the top and also the bottom of the CBU section and find that the bottom half of the CBU on Naxos records higher peak high-pressure (HP) of about 4 kbar than the top of the unit, defining the thickness of the CBU section on Naxos to about 15 km in the Eocene. ... mehr


Verlagsausgabe §
DOI: 10.5445/IR/1000135229
Veröffentlicht am 13.07.2021
Originalveröffentlichung
DOI: 10.1016/j.lithos.2021.106043
Scopus
Zitationen: 6
Web of Science
Zitationen: 5
Dimensions
Zitationen: 6
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Angewandte Geowissenschaften (AGW)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 04.2021
Sprache Englisch
Identifikator ISSN: 0024-4937
KITopen-ID: 1000135229
Erschienen in Lithos
Verlag Elsevier
Band 386-387
Seiten Art.-Nr. 106043
Vorab online veröffentlicht am 16.02.2021
Nachgewiesen in Web of Science
Dimensions
Scopus
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